Changes In Volatile Composition Research Articles

Changes in Flavor and Volatile Composition of Meat and Meat Products Observed after Exposure to Atmospheric Pressure Cold Plasma (ACP).

Studies on the atmospheric pressure cold plasma (ACP) exposure of meat and meat products mainly determine microbial inactivation, lipid oxidation, and meat color. Some studies include sensory evaluation, but only a few determine the changes in volatile composition due to ACP treatment. The results of sensory evaluation are inconclusive and range from "improvement" to "off-odor". This could be due to differences in the food matrix, especially in processed foods, or different experimental settings, including inadvertent effects such as sample heating. The few studies analyzing volatile composition report changes in alcohols, esters, aldehydes, and other compounds, but not necessarily changes that are novel for meat and meat products. Most studies do not actually measure the formation of reactive species, although this is needed to determine the exact reactions taking place in the meat during ACP treatment. This is a prerequisite for an adjustment of the plasma conditions to achieve antimicrobial effects without compromising sensory quality. Likewise, such knowledge is necessary to clarify if ACP-exposed meat and products thereof require regulatory approval.

Encapsulation of Cumin (Cuminum cyminum L.) Seed Essential Oil in the Chickpea Protein-Maltodextrin Matrix.

Isoelectrically precipitated chickpea protein isolate (CPI) and its combination with maltodextrin (MD) were investigated for the ability to form and stabilize cumin seed oil emulsions. Solubility, net surface charge, emulsion activity/stability indices, and creaming stability of CPI at a pH of 3.0-9.0 were evaluated. Optimum conditions for minimum cream separation were identified as: 0.19% CPI and 6.83% oil concentrations. Cumin (Cuminum cyminum L.) seed essential oil was microencapsulated within the CPI-MD matrix via spray drying. Effects of CPI-MD matrix formulation on the physicochemical characteristics and volatile composition of the microencapsules were investigated. CPI-MD matrices had positive effects on microcapsule properties such as relatively lower surface oil, higher encapsulation efficiency (EE), and oil retention. Approximately 86.6-96.4% oil retention and 90.9-98.4% EE were achieved. Optimum conditions for maximized oil retention (92.9%) and EE (98.6%) were identified as: 2.1% CPI, 14.8% essential oil, and 35% MD. GC-MS analysis of microcapsules was carried out to determine the changes in volatile composition during spray drying. Cymene, α-pinene, β-pinene, sabinene, terpinene, terpineol, phellandrene, and cumin aldehyde were determined as the major components. Optimized design showed the highest EE and minimal changes in the volatile composition of cumin seed essential oil.

Effect of Dielectric Barrier Discharge Plasma Treatment in Pasteurized Orange Juice: Changes in Volatile Composition, Aroma, and Mitigation of Off-flavors

Effect of Dielectric Barrier Discharge Plasma Treatment in Pasteurized Orange Juice: Changes in Volatile Composition, Aroma, and Mitigation of Off-flavors

Analysis of the aroma volatile compounds in different stabilized rice bran during storage

Rice bran is rich in nutrients and bioactive components, which plays an important role in reducing dyslipidemia and regulating intestinal flora. However, due to the rice bran’s instability resulting from rancidity during storage, the development is limited. E-nose, GC–MS and E-tongue were used to monitor the flavor and bitterness of different stabilized rice bran during accelerated storage, and the change of physicochemical properties in rice bran was determined. The rice bran flavor significantly changed after five stabilization treatments. The bitterness increased during storage, but the growth was small (from 7.39 to 7.62). Besides, after stabilization treatments, lipase (LA) activities gradually decreased from 10.11 to 2.03 mg/g, and lipoxygenase (Lox) activities decreased from 3.71 to 1.38 U/g. These results comprehensively elucidate changes in volatile composition, bitterness and physicochemical properties of stabilized rice bran samples during storage and lay the foundation for improving its acceptability and edibility in the future.

Changes in Volatile Composition of Cape Hake Fillets under Modified Atmosphere Packaging Systems during Cold Storage.

Fresh ready-to-cook fish fillets are susceptible to loss of freshness and accumulation of off-odour due to accelerated microbial spoilage. Suboptimal storage temperature and packaging conditions accelerate this process, limiting the economic potential. This study investigated the effects of modified atmosphere packaging (MAP) and storage temperature (0 °C and 4 °C) on the volatile compounds (VOCs) of Cape hake (Merluccius capensis) fish fillets as a predictor of shelf life and quality. Fresh Cape hake fillets were packaged under active modified atmosphere (40% CO2 + 30% O2 + 30% N2) and passive modified atmosphere (0.039% CO2 + 20.95% O2 + 78% N2) with or without an absorbent pad and stored at 0 °C and 4 °C for 12 d. The results obtained demonstrated that changes in VOCs and concentration were significantly (p < 0.05) influenced by MAP conditions, storage temperature and duration. A total of 16 volatiles were identified in the packaged Cape hake fillets: 4 primary VOCs and 12 secondary VOCs. The spoilage VOCs identified include tri-methylamine (TMA) (ammonia-like), esters (sickeningly sweet) and sulphur group (putrid). The concentration of secondary VOCs increased continuously during storage. Active-MA-packaged fillets performed better and had lower TMA values of 0.31% at 0 °C on day 12 in comparison to 7.22% at 0 °C under passive on day 6. Ethyl acetate was detected in passive-MA-packaged fillets stored at 0 °C on day 3, and the levels increased to 3.26% on day 6, while active-MA-packaged fillets maintained freshness. This study showed that in conjunction with TMA, VOCs such as esters and sulphur-related compounds could be used as spoilage markers for Cape hake fish fillets.

Assessing the volatile composition of seaweed (Laminaria digitata) suspensions as function of thermal and mechanical treatments

Macroalgae are a rich source of dietary fibre, protein, lipids and bioactives. However, more research is needed to understand how processing methods impact macroalgae techno-functional properties. In this work, aqueous suspensions of the fibre-rich brown algae Laminaria digitata were prepared by conventional food processing methods. The impact of sequence of processing steps (thermal and mechanical treatments), and heating time (15, 30 and 45 min), on volatile aroma composition were investigated. Changes in volatile composition were monitored with headspace GC-FID/MS analysis. Our results showed that both parameters impacted the volatiles profile of the suspensions. From an overall volatile perspective, short heating times (90 °C for 15 min) led to similar profiles, independently of the sequence of thermal and mechanical treatments. However, longer heating times induced a larger release of several aldehydes, specific for each processing method. Our results bring new insights on the volatile composition of suspensions of Laminaria digitata, which are related to flavour properties, and aid design of food products containing seaweed.

Volatile composition changes in lemon during fruit maturation by HS-SPME-GC-MS.

Volatiles are determinants of fruit aroma and flavor characteristics and also provide valuable information for lemon as ingredient for the food and drinks industry. Volatiles in 'Eureka' lemon and 'Xiangshui' lemon pulps from 130 to 186 days after flowering were enriched by headspace-solid-phase microextraction (HS-SPME), and analyzed by gas chromatography-mass spectrometry (GC-MS). Seventy-seven volatiles of two lemon cultivars at the different ripening stages were identified and divided into six categories. Varieties and ripening stages had significant effects on individual volatiles in each category. The proportion of monoterpenes was found to be higher in 'Eureka' lemon, while 'Xiangshui' lemon had a higher proportion of sesquiterpenes, aldehydes and alcohols. The proportion of monoterpene fluctuation decreased during fruit ripening, while fluctuation of sesquiterpenes, alcohols, aldehydes and esters increased. Among the hydrocarbons, monoterpenes decreased their relative abundance from 91.67% to 81.04% in 'Eureka' lemon, and from 83.01% to 60.04% in 'Xiangshui' lemon; conversely, sesquiterpenes increased from 0.73% to 2.89% in 'Eureka' lemon, and from 3.21% to 8.48% in 'Xiangshui' lemon. Among the oxygenated volatiles, the proportions of alcohols, aldehydes and esters were higher at 186 days after flowering in both two cultivars. The volatile organic compounds during fruit ripening of lemon varieties with different resistance were elucidated. The proportion of oxygenated volatiles increased during fruit ripening, and disease-resistant varieties had a higher proportion. These results provided important theoretical support for the utilization of lemon fruits and the innovation of disease-resistant germplasm resources. © 2021 Society of Chemical Industry.

Volatile composition changes of fruits in a biopolymer-coated polyethylene active packaging: Effects of modified atmosphere and packaging-shaped bacterial community

The potential impacts of active packaging on the volatile composition of fruits during preservations largely associated with consumers’ acceptance, yet was barely investigated. In this work, a biopolymer-coated polyethylene active film was developed and its effects on qualities and volatile compositions of fruits with different respiration rates were comprehensively investigated. Underlying reasons for the effect of active packaging on volatile composition change of fruits were elucidated through revealing ternary relationship among the packaging-shaped bacterial community, modified atmosphere and volatiles. Off-flavor production was reduced and more sesquiterpenes (α-cubebene, copaene, β-caryophyllene, α-caryophyllene, d-amorphene) were reserved for longan packaged with active film, due to its antimicrobial and moisture absorption ability, as leading contributors to the selective inhibition on spoilage bacteria genera including Zymobacter, Gluconobacter and Pantoea. Whereas volatile profile of strawberry with high respiration rate was more actively affected by the modified atmosphere induced by packaging, instead of the bacterial community, where hypoxia (<2% O2) led to the accumulation of ethyl esters (0.154–0.184 μg/g) that conferred off-flavor but decreased production of methyl (0.172–0.367 μg/g) and hexyl esters (1.26–1.89 × 10−2 μg/g) that represented typical fruity aroma. This work adds new knowledges on impacts of active packaging on the volatile profile of fruits and would provide guidance to smart design of active packaging for preservation of aromatic fruits.

Investigation of the changes in volatile composition and amino acid profile of a gala-dinner dish by GC-Ms and LC-MS/MS analyses

This study aimed to investigate the changes in volatile composition and amino acid profile of a dish “duck breast, beetroot mille-feuille” prepared in the Turkey Gala Dinner of an international gastronomy association. The ingredients collected from bazaars and chain markets were prepared and processed according to the original recipe. In raw ingredients and cooked products (P1, P2, and P3), volatile organic compounds were semi-quantitatively by GC-MS and amino acids quantitively by LC-MS/MS. The volatile composition and amino acid profile between P1, P2, and P3 products were tested with one-way ANOVA using SPSS version 20.0. In the final product, the dominant volatiles was found to be oily, waxy with lard and tallow notes (oleic acid), floral (squalene), and green-floral and citrus-floral (9-octadecenamide). In contrast, the dominant amino acid profile exhibited bitter-sweet and bitter-salty-sour tastes. The statistical test showed that the volatile composition among the product groups was not interrelated (p = 0.613412 > 0.05), whereas the amino acid profile was related (p = 0.067352 < 0.10). Overall, our study revealed that the desirable taste of the Gala-dinner dish “duck breast, beetroot mille-feuille” was formed by the co-existence of some dominant volatiles belonging to the fatty acid, triterpenoid, and fatty amide groups and some predominant amino acids, including valine, glutamic acid, aspartic acid, leucine, and lysine, as well as depending on the preparation and cooking conditions.

Effects of manufacturing on the volatile composition of raw Pu-erh tea with a focus on de-enzyming and autoclaving–compressing treatments

Volatile compounds largely contribute to the aroma of raw pu-erh tea (RPT). However, the changes of volatile composition during manufacturing are unclear. This work characterized 58 volatile compounds in the RPT samples collected from withering, de-enzyming, sun-drying, and autoclaving–compressing stages. Results show that de-enzyming and autoclaving–compressing have large effects on the volatile composition, with the total volatile contents sharply decreased by 76.68% and 35.77%, respectively. After de-enzyming, the relative content of aldehydes increased by 4.68-fold, whereas that of alkenes decreased by 2.65-fold; thus, the attractive fatty aroma must be enhanced while weakening the unpleasant grassy aroma. The volatile composition would be greatly changed by autoclaving–compressing, which is a special step for RPT production but rarely studied before. These findings revealed the changes of the volatile composition of RPT during manufacturing, especially de-enzyming and autoclaving–compressing, which are important for the formation of the aroma characteristics of RPT.

Changes of the Aroma Composition and Other Quality Traits of Blueberry 'Garden Blue' during the Cold Storage and Subsequent Shelf Life.

The changes of volatile composition and other quality traits of blueberry during postharvest storage were investigated. Blueberries were packaged in vented clam-shell containers, and stored at 0 °C for 0, 15 and 60 days, followed by storage at room temperature (25 °C) for up to 8 days for quality evaluation. The firmness, pH, and total soluble solids increased by 8.42%, 8.92% and 42.9%, respectively, after 60 days of storage at 0 °C. Titratable acidity decreased 18.1% after 60 days of storage at 0 °C. The volatile change was monitored using headspace–solid-phase microextraction–gas chromatography–quadrupole time-of-flight–mass spectrometry (HS-SPME-TOF-MS) and off-odor was evaluated by sensory panel. Volatile compounds generally showed a downward trend during cold storage. However, the subsequent shelf life was the most remarkable period of volatile change, and was represented by the strong fluctuation of ethyl acetate and the rapid decrease of terpenoids. Extending storage from 15 to 60 days under cold condition still resulted in an acceptable odor. However, subsequent storage at higher temperature resulted in a quick deterioration in sensory acceptability. The results proved that cold storage was a reliable way to maintain the quality of blueberry, and flavor deterioration during subsequent shelf life was more fatal to the blueberry flavor.

Comparative transcriptome analysis of genes involved in volatile compound synthesis in blueberries (Vaccinium virgatum) during postharvest storage

• Genes involved in postharvest blueberry aroma biosynthesis were characterized. • Increased ethyl acetate was associated with increased PDC activity after harvest. • Postharvest storage modulated terpene synthase (TPS) genes associated with linalool. Transcriptional regulation of aroma formation genes during postharvest storage remains poorly understood in the blueberry. In order to have a better understanding of the transcriptional regulation processes that occur in rabbiteye blueberry during storage and their effect on the volatile composition change, we performed volatile metabolite profiling and transcriptomic analysis. Our study reveals that during postharvest storage, ‘Garden blue’ blueberry volatile composition changed by regulating several secondary metabolic pathways, in particular, by stimulating the expression of pyruvate decarboxylase (PDC) genes, resulting in a high production of ethyl acetate. Postharvest storage also modulated some terpene synthase (TPS) genes associated with linalool production. The concentration of C6 aldehydes and alcohols decreased during the postharvest storage accompanied by lower lipoxygenase (LOX) gene expression. These findings illustrate the molecular and biochemical mechanisms that occur in blueberry during the postharvest storage period, especially with regard to volatile composition changes.

Volatile composition changes in navel orange at different growth stages by HS-SPME–GC–MS

This study investigated the changes in volatile organic compounds (VOCs) of navel orange during fruit maturation. The volatiles in navel orange from July (young fruit period) to November (commercial maturation period) were separated by headspace solid-phase microextraction (HS-SPME) and analyzed using gas chromatography–mass spectrometry (GC–MS). Fifty-seven VOCs were identified and classified into five groups. Through principal component analysis, the samples of different months were discriminated, and one-way analysis of variance showed that 55 volatiles significantly differed during growth. Among the VOCs, the relative concentration of monoterpenes increased with maturity, and D-limonene was the component with the highest content. Similar behavior was exhibited for aldehydes, reaching the maximum content in November. On the contrary, esters decreased its concentration from July to November. The concentration of sesquiterpenes gradually increased, reaching the maximum level between August and November. Moreover, alcohols reached theirs largest content in September, β-Linalool had the highest content among the alcohols. These results provided important theoretical support for the development of navel orange components and comprehensively elucidate the flavor characteristics during the ripening of navel orange.

Changes in volatile composition during the processing and storage of black ripe olives.

The present study revealed the effects of each step of black ripe olive processing (preservation, darkening, packing + sterilization) and storage on the volatile composition of two olive cultivars (Manzanilla and Hojiblanca). The preservation step enriched the volatile profile of the olives, mainly in ethyl acetate, methyl acetate, and ethanol. The darkening step produced the total or partial elimination of 55-65% of the volatiles identified before this step. Around 70% of the volatiles in the final products corresponded to compounds that were formed or increased significantly as a result of the sterilization treatment at 121 °C. Although differences in the volatile compositions and contents between Manzanilla and Hojiblanca were found, the dominant volatiles in both cultivars were benzaldehyde, dimethyl sulfide and ethyl acetate. Storage for 8 months had little influence on their volatile profiles, although the stability of individual volatiles in Manzanilla was better than that in the Hojiblanca cultivar.

Influence of environmental factors on the volatile composition of two Brazilian medicinal plants: Mikania laevigata and Mikania glomerata.

Mikania laevigata Sch.Bip. ex Baker and Mikania glomerata Spreng. are medicinal plants popularly known as guaco, used for inflammatory diseases of the respiratory system, included in pharmaceutical formularies and often used without distinction. However, several studies show that the chemical composition varies between these species, as well as in plants are subjected to different environmental stresses. Few studies have been carried out with the volatile compounds of guaco, even less about the changes in volatile composition due to abiotic variation. The aim of this work was to evaluate how volatile compounds vary according to the seasons and at different times of the day and if these compounds are influenced by the variations in the growth conditions such as: temperature, luminosity and water. The headspace volatiles of the leaves were sampled by solid phase micro extraction and analyzed by gas chromatography-mass spectrometry. Untargeted metabolomic analysis of the resulting chromatograms and chemometrics was applied. The chemical profile of the volatiles of M. laevigata and M. glomerata were different; being clearly separated in the exploratory grouping analyzes (PCA), followed by analysis of variance of the marker compounds of both species. Only M. laevigata contained coumarin, considered to be the chemical marker of both species and to be responsible for the therapeutic activities. There was no significant difference between the morning and afternoon collections of either species. Coumarin, α-pinene and bicyclogermacrene were more intense in the volatiles of M. laevigata throughout the year and responsible for grouping the samples of this species. For M. glomerata, hexanal and 2-hexenal were responsible for grouping the samples and were more intense in all months. The growth conditions tested affected the intensity of specific compounds in the chromatograms. Some compounds were less intense with the increase of the temperature and in the plants subjected to full sunlight. However, certain volatile compounds-such as pinenes-were more intense in plants suffering drought. The variation in composition between species of guaco was greater than those observed in the seasonal and cultivation studies, indicating that these species cannot be used indistinctly.

Respiration rate and changes in composition of volatiles during short-term storage of minimally processed root vegetables

Respiration rate and changes in composition of volatiles during short-term storage of minimally processed root vegetables

Effects of Soil NPK Supply on Pinot noir Wine Phenolics and Aroma Composition

This work evaluated the impact of vine nitrogen (N), phosphorous (P), and potassium (K) supply on Pinot noir wine composition. Pinot noir grapevines were grown in a pot-in-pot system for three years and fertigated with varying levels of N, P, or K supply while holding all other nutrients constant. N was varied from 7.50 mM total N supply (Control) to as low as 1.125 mM total N in five discreet levels, while P and K supply were each varied in four levels, with the lowest rate (0 mM) during fertigation events. Wines produced in each of the three years were analyzed. N supply had a major impact on wine composition, including effects on volatile compounds, especially fermentation-derived esters and higher alcohols. Lower rates of N supply increased the total phenolic content in wine; in general, reduced N supply led to a decrease in straight-chain esters and alcohols, but to an increase in branched-chain esters and alcohols in wine. Low-N wines also had lower levels of volatile sulfur compounds in two of the three years. N supply also affected some grape-derived compounds in wine. Reducing N supply resulted in lower concentrations of β-damascenone across all years, but the effect of N supply on monoterpenes was not consistent from year to year. Altering P supply did not have reproducible effects on wine volatiles. Changes in volatile composition in response to nutrient supply could ultimately affect aroma perception and overall wine quality, which will require further exploration.

Comparison of Volatile Compounds Profile and Antioxydant Activity of Allium sativum Essential Oils Extracted using Hydrodistillation, Ultrasound- Assisted and Sono-Hydrodistillation Processes

Abstract: Objective: This work aims to evaluate the impact of the use of ultrasound during essential oils extraction from garlic bulbs. Material and methods: The essential oils were extracted by Conventional Hydrodistillation method (HD), Ultrasound-Assisted hydro-distillation (US-HD) and Sono-hydrodistillation (SHD) and compared using yield profile, chemical composition and antioxidant activity. Results: Higher performances were obtained when the direct application of ultrasound were used. Indeed, SHD allowed a higher yield after only 30 min of extraction time against 70 min and 90 min for the US-HD and the HD respectively. Among the total identified compounds by GC/MS, Sulphur compounds were found to be the most abundant with qualitative similarities for the three processes. Essential oils showed a potential DPPH radical scavenging activity with IC50 values of 0.96, 1.17 and 1.23 respectively for the three HD, US-HD and SHD processes. Conclusion: The use of ultrasound for the extraction of essential oil from garlic reduced extraction time without causing significant changes in volatile composition and antioxidant activity. Keywords: Garlic essential oil, GC-MS, Antioxidant activity, Hydrodistillation, Ultrasound.

Changes in Composition of Volatiles in Grass Silages After Opening Silos

Changes in Composition of Volatiles in Grass Silages After Opening Silos

Physical Properties and Volatile Composition Changes of Cooked Sausages Stuffed in a New Casing Formulation Based in Surfactants and Lactic Acid During Long-Term Storage.

The objective of this research was to investigate the effects of different modified casings and storage time on the quality attributes of cooked sausages using principal component analysis (PCA) and discriminant analysis. The effects of modifying different casing treatments on sausages' color (L* , a* , b* ), pH, and texture (hardness, springiness, cohesion, gumminess, chewiness) after 36-d storage were estimated by PCA. According to the PCA, lightness at day 36 was correlated to sample stuffed in casing with treatment 2 (T2; soy lecithin concentration: 1:27.5, soy oil concentration: 1.25%, lactic acid concentration: 19.5 mL/kg NaCl [solid], residence time: 75 min). T2 sample can be distinguished from control sample at days 1, 8, 15, and 36 according to electronic nose system. DA was performed to determine possible different sample groups according to selected variables. Results showed that chewiness was the best discriminator for differentiating sausages stored for 15 d from other days. Chewiness and gumminess were able to discriminate sausages stuffed in casing with T2 from control sample. The relationships between modified concentrations and quality attributes of cooked sausages after 36-d storage were also established.